Emission electrode system



United States Patent Oiice 3,158,453 Patented Nov. 24, 19,64

3,158,453 EMISSIN ELECTRODE SYSTEM Sten Maartman, Klinten, and Stig Gustafsson, Jonkoping,

Sweden, assignors to Aktieholaget Svenska Flaktfabriken, Stockholm, Sweden Filed July 15, 1960, Ser. No. 43,169 Claims priority, application Sweden, Oct. 21, 1959,

9,805/59 3 Claims. (Cl. 55-112) The present invention relates to an emission electrode system for electric precipitators and comprises a plurality of electrodes suspended in frames. With the everincreasing overall height aimed at for electric precipitators, it has proved diflicult to provide for cleansing the electrodes by simple conventional means. In this connection especially the cleansing of the emission electrodes has involved a troublesome problem. As a matter of fact, the emission electrodes, for several reasons, cannot be constructed with the same mechanical rigidity, or stiffness, as it is possible to attain by simple expedients for the precipitation electrodes. Therefore, it has been necessary in the past to subdivide the emission electrode system into a plurality of sections, one above the other and each provided with its individual rapping device. Such construction, however, turns out to be very expensive. In addition, such a construction necessitates an unfavourable disposition of the elements forming part of the rapping device relative to the path of the gas flow through the electric precipitator.

The invention has for its object to enable cleansing of the emission electrodes by the use of one single beating device disposed adjacent the bottom ends of the electrodes. In this case the beating device can be of a design identical to that used for the precipitation electrodes which, of course, means saving of labour and expenses. The novel and characterizing feature of the emission electrode system according to the invention resides in that the electrodes are combined into units each containing two or more electrodes by means of members acting as stifleners. The stiiener may extend substantially throughout the length of the electrodes, or the emission electrodes may alternatively be combined by means of a plurality of stiieners distributed throughout the length of the electrodes.

The electrodes of the emission electrode system suitably consist of strips known per se having smooth or toothed edges and, in this case, the stiifener may be constituted by a sheet-metal strip of a configuration substantially the same as that of the precipitation electrodes used in the precipitator. The emission electrode system could also be made with the stiiener as an integral part of the emission electrodes.

The invention will now be described more closely with reference to the accompanying drawing showing by way of example one embodiment of the emission electrode system according to the invention and in which:

FIG. l is a vertical sectional view of a portion of a precipitator made in accordance with the present invention;

FIG. la is a vertical sectional view like FIG. 1 but showing another portion of the precipitator and a modiied form of reinforcing means;

FIG. 2 is an enlarged horizontal section through a number of electrodes arranged as in FIG. l or FIG. la, showing an emission electrode disposed between two precipitation electrodes.

FIG. 3 is a fragmentary side elevational view of the emission electrode of FIG. 2;

FIG. 4 is a view similar to FIG. 3 showing an emission electrode having toothed side edges.

FIG. 5 is a horizontal section on a reduced scale of the apparatus shown in FIG. l'.

In FIG. l two emission electrodes 1 of strip plate form are connected by a plate-like stiifener 2, as of sheet metal having its principal plane disposed transversely or at right angles to the planes of the electrode plates 1, to form a transversely stiff rigid unit 3.

FIG. la shows a form like that of FIG. 1 but in which the stitfeners 2a are made in short sections instead of continuous lengths to connect the plate electrodes 1a to form a rigid unit 3a. Said units at their top ends are pivotally mounted in a framework 4 which is insulated from the casing 5 of the electric precipitator. Numeral 7 designates a plurality of precipitation electrodes disposed on both sides of the emission electrodes. The electrodes are pivotally suspended from a framework 8 which is rigidly connected with the casing 5 of the electric precipitator. Numeral 9 designates a rapping or beating device of a conventional design for cleansing the emission electrodes. The rapping device is arranged to actuate a beating rod 10 disposed beneath the electrodes, this rod being made of double flat iron bars and provided with abutments 11 inserted between these bars. In the embodiment shown, the emission electrodes are suspended by means of sheet-metal brackets 13 engaging slots 14 formed in the framework 4. The beating device for the precipitation electrodes is of similar design, but both could be of any other suitable design of course.

The units 3 and 3a are generally similar. The units 3 at the left hand side of FIG. l include continuous stiffening members 2 coextensive with the electrodes 1. The units 3a at the right hand side of FIG. 1 include stitfening members 2a which are composed of a plurality of short sections disposed in spaced relation longitudinally of the electrodes 1a.

In FIG. 2 of the drawing, the parts shown are provided with reference numerals identical to those of FIG. l. The electrodes shown therein consist of sheet-metal strips having smooth edges 16 (see FIG. 3), as previously known per se. The electrodes may be modified as shown at 1b in FIG. 4 by providing teeth on the edges such as shown at 16h. The stilfening member 2 is of a configuration substantially the same as that of the precipitation electrodes 7 used in the precipitator.

What is claimed is:

l. An electrostatic precipitator comprising a casing adapted to have a gas to be cleaned owing therethrough, a plurality of emitting and collecting electrodes in said casing, means pivotally suspending said electrodes in said casing in rows aligned longitudinally with the direction of flow of gas to be cleaned, the rows in a direction transversely of the direction of gas flow being arranged in alternating rows of emitting and collecting electrodes, each row of said emitting electrodes comprising a plurality of longitudinally spaced substantially iiat strips disposed transverse to the direction of iow of the gas to be cleaned, interconnecting stiiening means secured between 4and uniting said strips in pairs, said stiflening means each comprising a sheet metal member having an intermediate web and attachment element on opposite sides of said intermediate web, said attachment elements each being secured to a respective one of said strips, rapping means operatively connected to the bottom ends of said emitting and collecting electrodes and arranged to rap the electrodes in the direction of the length of the rows of electrodes, said interconnecting stifening means forming with said strips units of suiiicient rigidity to permit effective cleaning of the units by rapping the lower ends of the full length units.

2. An electrostatic precipitator according to claim 1 wherein said stitfening member is continuous and coextensive with said emitting electrodes.

Y 3 3. An electrostatic precipitator according to claim 1 wherein said stiiening member comprises a plurality of short sections disposed in spaced relation longitudinally of the emitting electrodes.

References Cited in the le of this patent UNITED STATES PATENTS 4 2 Gannone Apr. 3, 1951 Richardson Apr. 29, 1952 Wintermute Feb. 9, 1954 Wintermute Nov. 16, 1954 Sohlman et a1. Nov. 5, 1957 FOREIGN PATENTS Great Bn'tain 1913 Great Britain Apr. 4, 1956 France Feb. 25, 1946 UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3, 158,453 November 24 1964 Sten Maartman et altl It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 12, strike out "is" and insert instead injits turn, is carried suspension rods 6 n l Signed and sealed this 13th day of April 1965.

(SEAL) Attest: Y I

ERNEST W. SWIDERI EDWARD J BRENNER i Attestin Officer Commissioner of Patents n 

1. AN ELECTROSTATIC PRECIPITATOR COMPRISING A CASING ADAPTED TO HAVE A GAS TO BE CLEANED FLOWING THERETHROUGH, A PLURLAITY OF EMITTING AND COLLECTING ELECTRODES IN SAID CASING, MEANS PIVOTALLY SUSPENDING SAID ELECTRODES IN SAID CASING IN ROWS ALIGNED LONGITUDINALLY WITH THE DIRECTION OF FLOW OF GAS TO BE CLEANED, THE ROWS IN A DIRECTION TRANSVERSELY OF THE DIRECTION OF GAS FLOW BEING ARRANGED IN ALTERNATING ROWS OF EMITTING AND COLLECTING ELECTRODES EACH ROW OF SAID EMITTING ELECTRODES COMPRISING A PLURALITY OF LONGITUDINALLY SPACED SUBSTANTIALLY FLAT STRIPS DISPOSED TRANSVERSE TO THE DIRECTION OF FLOW OF THE GAS TO BE CLEANED, INTERCONNECTING STIFFENING MEANS SECURED BETWEEN AND UNITING SAID STRIPS IN PAIRS, SAID STIFFENING MEANS EACH COMPRISING A SHEET METAL MEMBER HAVING AN INTERMEDIATE WEB AND ATTACHMENT ELEMENT ON OPPOSITE SIDES OF SAID INTERMEDIATE WEB, SAID ATTACHMENT ELEMENTS EACH BEING SECURED TO A RESPECTIVE ONE OF SAID STRIPS, RAPPING MEANS OPERATIVELY CONNECTED TO BOTTOM ENDS OF SAID EMITTING AND COLLECTING ELECTRODES AND ARRANGED TO RAP THE ELECTRODES IN THE DIRECTION OF THE LENGTH OF THE ROWS OF ELECTRODES, SAID INTERCONNECTED STIFFENING MEANS FORMING WITH SAID UNITS OF SUFFICIENT RIGIDITY TO PERMIT EFFECTIVE CLEANING OF THE UNITS BY RAPPING THE LOWER ENDS OF THE FULL LENGTH UNITS. 